One task that world leaders must perform and perform well is that of handling situations without blinking an eye or missing a beat.

President Obama's ability to do this might have been tested Tuesday night as he greeted people on a Denver street during a visit there to meet supporters and raise money for Democratic U.S. Senate candidates.

The president shook hands with men, women and, at one point, a man wearing a horse head mask. Obama appeared to chuckle as he spotted the man, who wore a red T-shirt, and wore a quizzical but amused look on his face as he shook hands with the masked man.

In photos captured on the scene, it's not clear if the man said anything to the president and, if so, what he might have said.

One thing is clear, though, is that the photo went viral as soon as it became public.

Around the Internet, photos of people wearing horse masks appear as a gag. In one famous case, a man in Aberdeen, Scotland, spotted a car driving by as it captured photos for use on Google Street View, an Internet mapping service. The man, who happened to have a horse head mask with him, decided on a whim to put it on as the camera captured geographic locations, according to the website knowyourmeme.com.

Like the images of President Obama's encounter, the images of the Scotland man, who now has a blog and is nicknamed Horse Boy, went viral.

After leaving the masked man and moving on, President Obama headed to a bar to have beer and shoot pool with Gov. John Hickenlooper.